Three viscometers, 1885-1911.
© Science Museum / Science & Society Picture Library
These items are all asociated with Sir Boverton Redwood (1846-1919). The two to the right are the first experimental viscometers, made by Redwood around 1885, working on a design by Charles Rumble. To the left is the commercial form adopted by the Admiralty for use with heavy oils. It has an improved water jacket and thermometer fittings. Viscosity was measured by timing the flow of a known quantity of oil at a standard temperature.